Central Location/hub for SMS and Voicemail

Im a small business owner and looking to have one central location or hub that is shared between multiple users (extensions). For example: Phone calls, SMS, Voicemail, and missed calls can be viewed and responded by all users under one umbrella. Currently and specifically SMS & Voicemails go to one specific extension (say extension 101, but ex 102 should also have access to those SMS and Voicemails) and only that extension has access to it, which clogs the system of communication. ALL extensions should have the ability to hear voicemails and respond to SMS in the central location or hub. This way multi extensions can respond to text and if desired different extensions can chime into the text if needed.